Numerous applications require a durable, effective seal between an outer stationary housing containing a fluid reservoir and a rotatable and axially movable shaft within the housing. A typical application is in a wheel oil seal between the axle of a motorized vehicle and an outer surrounding spindle where it is important to prevent contaminants, such as, dirt, water, dust from flowing inwardly past the inboard side of the spindle and into the spindle so as to subject bearings, axles or other components to damage or extreme wear; and further to prevent the flow of oil and grease out of the inboard side of the spindle thereby aiding in the protection of parts inside the spindle and on the outboard side of the spindle. It is therefore desirable to construct a seal assembly with a seal ring which has the ability to maintain a constant pressure both in axial and radial directions so as to remain seated irrespective of any pulsating or translational movement of the axle as it moves inwardly or outwardly with respect to the spindle. Further, it is important that a constant pressure be maintained over the entire circumference of the seal ring notwithstanding any axle biasing which may occur in a radial direction as the axle spins. The seal must further remain seated notwithstanding changes in atmospheric pressure or changes in pressure which may occur as a result of translational axle movement. Rotary or shaft seals have been devised which employ a boot or diaphragm where one end of the diaphragm is attached and the other is free to slide axially in response to shifting between a shaft and outer housing. Representative of such seals are those disclosed in U.S. Pat. No. 2,984,506 to R. H. Andresen et al. Other representative patents are U.S. Pat. Nos. 2,399,764 to R. Schilling; 2,695,799 to A. M. Chambers et al; 2,994,547 to L. N. Dolhun et al; 3,355,178 to J. R. Hornaday; 3,370,856 to G. E. Buske; 3,887,200 to F. S. Engelking et al; 4,095,807 to S. Jandt et al; and 4,275,889 to G. K. Butler et al. Also seal rings have been devised for sealing between end surfaces of a rotary member and stationary member, such as, those disclosed in U.S. Pat. Nos. 4,243,233 and 4,212,473 to Y. Aria. It is proposed in accordance with the present invention to employ a rotary seal assembly made up of a combination of a boot or diaphragm-type seal which is fixed at one end to one of a stationary and rotary member with the other end bearing against a seal ring, the seal ring having a tapered surface which engages a correspondingly sloped surface on the other of the stationary and rotary members. The interface between the boot and seal ring are effectively fixed against relative movement in an axial direction, but the boot is free to be displaced with respect to the seal ring in a radial direction and is further capable of flexing in response both to axial and radial movement. In this way, the seal ring is capable of remaining seated notwithstanding pulsating or translational movement of the axle and can maintain a constant pressure over its entire circumference notwithstanding any axle biasing which may occur in a radial direction as the axle is rotated.